Automatic air-brake.



, PATENTED JAN. 1, 1907'.

' A. PARKER-SMITH. AUTOMATIG AIR BRAKE.

APPLIOATIbH FILED APR.23,1906.

Fig J.

$1M: o w

UNITED STATES PATENT OFFICE.

AUGUSTUS PARKER-SMITH, OF NEW YORK, N. Y., ASSIGNOR, BY MESNEASSIGNMENTS, TO SAUVAGE' SAFETY BRAKE COMPANY, A CORPORA- TION' or NEWJERSEY.

Specification of Letters Patent.

Patented Jan. 1, 1907.

Application filed April 23, 1906. Serial No. 313,116-

To all whom it may concern.-

Be it known that I, AUGUSTUS PARKER- SMITH, a citizen of the UmtedgStates of America, and a resident of the borough of Manhattan, city,county, and State of New York, have invented certain new and usefulImprovements in Automatic Air-Brakes, of which the following is aspecification.

My invention relates generally to fluidpressure brakes for cars, andmore specifically comprises a simple mechanism for automatically varyingthe brake power or pressure upon the brake-shoes approximately inproportion to the weight of the car.

It is well known that many cars, such as the heavy coal-cars now in use,weigh when loaded approximately three times what the car alone weighsempty. As standard practice forbids the application to the brakeshoes ofa pressure more than ninety per cent. of the weight carried by thewheel, it is evident that the brake equipment can only be such as willproduce this maximum for the empty car and that when said car is loadedthe brake-shoe pressure will then be only thirty per cent, instead ofninety per cent. of

the weight carried upon each wheel, and accordingly the brakes will havebut slight retarding effect upon such loaded cars. Various mechanismshave been devised for causing the varying weight of the car to produce ashifting leverage in the brake system or to control the flow of air tothe cylinder; but these, so far as I am aware, have not gone intogeneral use by reason of their complication and more or less uncertainaction. I have invented a simple positive means of accomplishing thisresult which operates, broadly speaking, on the principle of theinstallation of a second cylinder and piston and the employment ofpositive looking or restraining means for holding the piston of thesecond cylinder out of action when the car is empty and allowing it tohave its natural amount of travel when the car is loaded, and so throwinto operation the power of said second cylinder.

The best form of apparatus embodying this invention at present known tome is illustrated in the accompanying sheet of.

drawings, in which Figure 1 is a plan view of a brake-rigging embodyingmy invention. Fig. 2 is a vertical detail section showing the operatingparts in the position assumed when the car is empty or lightly loaded.Fig. 3 is a similar view showing the position of similar parts when thecar is loaded, and Figs. 4 and 5 are modifications.

Throughout the drawings like referencefigures indicate like parts.

1 represents the main cylinder, and 2 the auxiliary cylinder, which ispreferably thrown into action after the movement of the piston in thefirst cylinder has begun, the air passing over from the first to thesecond cylinder through the pipe 19, all in the manner set forth in theReissued Letters Patent to William H. Sauvage, No. 12,229, dated June 7,1904, and 3 represents the adjacent portions of the brake-rigging; 4, anauxiliary lever 5, a link by which the same is connected to thebrakerigging.

6 is a push-rod connected to the auxiliary lever 4 and telescoping intothe hollow piston 7 in the cylinder 2 when the said piston is shovedhome. This telescoping action is brought about by the push-rod latch 8riding up over the trip 9 when the piston is pushed in, as shown in Fig.2, but dropping out so as to engage the piston when the pushrod ispulled out by the movement of the piston in the first cylinder, thelatch 8 then taking the position shown in Fig. 3.

10 is a latch, which I will call the cut-out latch, which is pivoted tothe auxiliary cylinder 2 and adapted to have its hooked end fall overand engage the end of the hollow piston 7. This latch is lifted out ofengagement by means of any convenient mechanism operated by the loadingand unloading of the carsuch, for instance, as the cord or wire 15,passing through the guide 16 16* on the car-body 11, the loop in the endof the bracket 18, carried by the truck-bolster 13 and connected to thebolster 12 or other convenient portion of the car-body. 14 representsthe ordinary car-supporting springs, which carry the weight of the car.

In the modification shown in Fig. 4, 20 is any convenient form of springpanel or trap in the bottom or side 21 of the car-body, which isnormally held up by spring 22 engaging the bell-crank 23, extending fromsaid spring-trap, which is hinged at 24. In this case the cord 15 isconnected to the bellorank 23.

The operation of my invention is as follows: When the car is empty andthe springs 14 are expanded, as shown in Fig. 2, the cord 15 is allowedto run out to the left, and the restraining or cut-out latch 10 dropsinto the position shown in said Fig. 2. This locks the piston 7 in itsinnermost position, and when air is admitted to the main cylinder 1 itoperates to apply the brakes with the power of its piston; but thepush-rod 6 moves idly in and out of the hollow piston 7, and no power isapplied by the second cylinder. When, however, the car is heavily loadedand the springs are compressed, as shown in Fig. 3,'the cord 15 ispulled to the right, lifting up the restraining-latch 10 out of the pathof the piston 7, and when the brakes are applied the second piston movesout and applies its power to the brake-rigging in the manner set forthin the Sauvage patent, above referred to.

In the modification shown in Fig. 4 the same result is produced by theelevation or depression of the spring panel or trap 20, which is forceddown by the load of coal or other material in the car-body or forced upby the spring 22 when the car-body is empty.

As shown in Figs. 1, 2, and 8 of the drawings, the wire-or cord 15extends in both directions from the brake-cylinders and should beoperatively connected to both trucks. As indicated in Figs. 2 and 3,said cord may be arranged in one continuous loop, which runs through theguide 16 in opposite direotions and has its bight connected with thecut-out latch 10. This special arrangement would have the effect ofproducing upon the cut-out latch a lifting action amounting to the meanor average effect of the depression of the springs at the two ends ofthe car. Thus if the car was so loaded that one truck was fullydepressed and the other not at all the latch would be lifted one-half ofthe full distance. If one end of the car were fully depressed and theother half-way depressed, the latch would be lifted three-quarters ofthe full distance. These and other variations in theextent of depressionof the springs might be caused to modify the action of the brake so asto produce varying pressures between that of the main cylinder alone andthe full power of the two cylinders by employing a modified form ofcut-out-latch, (shown in Fig. 5,) where the outer hook or projection 10extends farther than the inner hook or projection 10 so that a partiallift of the latch will free the piston of the second cylinder fromengagement with the inner hook 10 but Will limit its outward travel byreason of its contact with the outerhook 10 Thus limiting the travel ofthe second cylinder Will of course limit the pressure which can beapplied by it to the slightly elastic brake-rigging and brake-beams, andso produce an intermediate brake-pressure between the two extremes,which will be applied when the car has an intermediate load somewherebetween its weight empty and fully loaded.

The advantages of my invention comprise its cheapness, simplicity,positiveness in action, and case of repair by unskilled labor in caseanything breaks.

It is evident, of course, that various changes could be made in thedetails of construction illustrated and described without departing fromthe spirit andscope of my invention.

Other forms of mechanism for positively withholding the second pistonfrom movement might be'substituted, theseoondpiston might be operated byother means than air admitted from the first cylinder, other forms ofconnecting the second piston with the brake-rigging might be employed,and other mechanism'for drawing the restraining-latch into and out ofengagement might be devised. All these and other similar modifications Ishould stillregard as being within the boundaries of my invention.

In case the bearing-springs 14 werein the truck-frame, as in someconstructions now in use, then 12 would represent the truck-bolster, and13 a bar carried by the wheel-axles of the truck. It is also obviousthat the sprin 22 might be replaced by other equivalent mechanismtending normally to overbalance the weight of the panel 20 alone.- In

short, the weight of the cut-out latch 10- might be made great enough toaccomplish this, and so do away with spring 22.

Having therefore described my invention,

I claim 1. In a fluid-pressure brake system for railroad-cars, thecombination with the brake-rigging, the main cylinder and piston, of asecond cylinder and piston and mechanism by which the thrust of saidsecond piston may be transmitted to the brake-rigging, means forpositively withholding thesecond piston frommovement, and mechanismubywhich said means may be thrown into or out of action.

2. In a fluid-pressure brake system for railroad-cars, the combinationwith the brake-rigging, the main cylinder and piston, of a secondcylinderv and piston and mechanism by which the thrust of said secondpiston may be transmitted to the brake-rigging, means for positivelyWithholding the second piston from movement, and mechanism by which saidmeans may be thrown into or out of action, together with connectionsthrough which said mechanism is operated by the load 011 the car.

3. In a fluid-pressure brake system for railroad-cars, the combinationwithv the brake-rigging, the main cylinder and piston, of a secondcylinder and piston and mechanism by which the thrust of said secondpiston may be transmitted to the brake-rigging, a locking device forpositively withholding the second piston from movement, and mechanism bywhich said locking device may be thrown into or out of action.

4. In a fluid-pressure brake system for railroad-cars, the combinationwith the brake-rigging, the main cylinder and piston, of a secondcylinder and piston and mechanism by which the thrust of said secondpiston may be transmitted to the brake-rigging, a locking device forpositively withholding the second piston from movement, and mechanism bywhich said locking device may be thrown into or out of action, togetherwith connections from said locking device to the car-springs by whichthe locking device is thrown out of action when the springs aredepressed, and into action when the springs are expanded.

5. In a fiuidpressure brake system for railway-cars, the combinationwith the brake-rigging, the main cylinder and piston, of a secondcylinder, and piston and telescoping piston-rod by which the thrust ofsaid second piston may be transmitted to the brake-rigging in aid of thefirst piston, but the first piston may move independently of the secondpiston, a locking-hook pivoted on the second cylinder and adapted tonormally engage the second piston, and means oper ated by the load onthe car to lift said hook out of such engagement and free the piston.

6. In a fluid-pressure brake system for railway-cars, the combinationwith the brake-rigging, the main cylinder and piston, of a secondcylinder, and piston and telescoping piston-rod by which the thrust ofsaid second piston may be transmitted to the brake-rigging in aid of thefirst piston, but the first piston may move independently of the secondpiston, a locking-hook pivoted on the second cylinder and adapted tonormally engage the second piston, and means operated by the load on thecar to lift said hook out of such engagement and flee the piston, saidmeans comprising connecting mechanism attached to the car-body andextending to the car-truck.

7. In a fluid-pressure brake system for railway-cars, the combinationwith the brake-rigging, the main cylinder and piston, of a secondcylinder, and piston and telescoping piston-rod by which the thrust ofsaid second piston may be transmitted to the brake-rigging in aid of thefirst piston, but the first piston may move independently of the secondpiston, a locking-hook provided with a series of projections ofdifferent lengths adapted to engage and limit the travel of the secondpiston, and means operated by the load on the car to lift said hook tovarying gears of disengagement with said second piston.

8. In a fluid-presssure brake system for railroadcars, the combinationwith the brake-rigging, the main cylinder and piston,

of a second cylinder and piston and mechanism by which the thrust ofsaid second piston may be transmitted to the brake-rigging, and meansfor positively graduating the movement of the second piston.

Signed at New York, N. Y. this 20th day of April, 1906.

AUGUSTUS PARKER-SMITH.

Witnesses:

FRANK OOoNNoR, M. G. CRAWFORD.

